It’s a debate that has rumbled on for a decade – and is at the very heart of our understanding of what makes us fat.
On one side, a group of diet experts who argue that our ever-more sedentary lifestyles are to blame for our spiralling obesity rates.
They say inactivity is so hugely damaging to health, leading to weight gain that increases the risk of everything from heart disease and diabetes to many cancers, it’s on a par with